: Although physicians, child protection workers, attorneys, and the public attribute great diagnostic and probative importance to medical examinations of children who have allegedly been sexually abused, few researchers have assessed the reliability of such examinations. In addition, because physicians routinely elicit histories of sexual contact before examining allegedly abused children, it seems possible that this information influences their diagnostic conclusions. No investigations of possible bias in examinations of sexually abused children have been reported. We propose (l) to measure the reliability of physicians' identification and interpretation of genital physical findings in girls and (2) to investigate the possibility of detection bias in genital examinations of girls by comparing physicians' identification and interpretation of genital physical findings that are linked alternately with histories that do and do not suggest sexual abuse. To accomplish these goals, we will ask 1,400 non-expert physicians and 400 physicians with substantial experience examining sexually abused children to complete brief demographic questionnaires, to identify genital abnormalities in 14 cases each consisting of a brief history and a colposcopic photograph of a girl's genitalia, and to rate in each case the consistency of the findings with a diagnosis of sexual abuse. The 14 cases will consist of two sets of seven cases mailed six weeks apart. The photographs in the first set will also be used in the second set, six linked alternately with highly specific histories of sexual abuse and with vague or non-suggestive histories and the seventh linked with the same history in each set. The investigators will use intra-class correlation coefficients to describe inter-physician agreement. To assess the presence of detection bias, they will use McNemar's test of correlated proportions and its Stuart-Maxwell extension. The results of this study will either strengthen confidence that medical examinations of sexually abused girls tend to be consistent and unbiased by historical information or will alert professionals to the potential for detection bias in such examinations and to the need to take such bias into account in clinical research, clinical practice, and judicial proceedings.